Field of the Invention
Embodiments disclosed herein relate to an imprinting apparatus configured to form a pattern on a resin on a substrate using a mold, a device fabrication method for fabricating a device by using the imprinting apparatus, and an imprinting method.
Description of the Related Art
The imprinting technology is known as a technology for fabricating devices such as semiconductor devices. The imprinting technology enables formation of a pattern on a resin by supplying an uncured resin onto a substrate and curing the resin in contact with a mold (corresponding to a reticle). For the imprinting technology, there are some imprinting methods such as thermal imprinting based on thermal deformation of a resin and photo-imprinting in which a resin is cured by light.
During fabrication of a device, a process of etching an underlying layer or implanting ions into a substrate is repeatedly performed using a pattern formed on a resin as a mask. Accordingly, it is essential to accurately align an upper-layer pattern relative to a lower-layer pattern in order to ensure the specs of a device.
In general, photolithography apparatuses have an alignment function for correcting a relative misalignment (alignment error) between a pattern on a reticle and a pattern on a substrate.
Imprinting apparatuses are also desired to have such an alignment function of photolithography apparatuses. Photolithography apparatuses do not bring a reticle into contact with a substrate, whereas imprinting apparatuses bring a mold into contact with a substrate with a resin interposed therebetween. Accordingly, Japanese Patent Laid-Open No. 2006-165371 discloses that a relative misalignment between a substrate and a mold is measured after the mold is brought into contact with a resin disposed on the substrate and alignment of the substrate and the mold is performed by correcting this misalignment before the resin is cured.
However, it was found that, even if a relative misalignment between a substrate and a mold is corrected after the mold is brought into contact with a resin and then the resin is cured, a relative misalignment between a pattern on the cured resin disposed on the substrate and a pattern on an underlying layer still occurs. At least one of major causes of this relative misalignment is related to shrinkage of a resin. After curing of a resin is started, the resin continues to shrink until it is fully cured (until the end of curing), and consequently stress is applied to the mold as the resin shrinks. It was found that this stress applied to the mold causes the relative misalignment between the substrate and the mold.
For this reason, a relative misalignment between a pattern on a cured resin disposed on a substrate and a pattern on an underlying layer needs to be inspected (overlay inspection). In the related art, the relative misalignment is inspected in the following manner. After patterns are transferred to all shot regions on a substrate by an imprinting apparatus, the substrate is transported into an overlay inspection apparatus different from the imprinting apparatus for inspection. Because inspection is performed after patterns are transferred to all shot regions and then the substrate is transported into the overlay inspection apparatus, the inspection of the relative misalignment takes time, resulting in a decrease in productivity.